The strength of adhesion between a label and an outside surface of a bottle is of considerable interest to adhesive manufacturers, bottling plants, marketers, compliance officers, and the like. For example, weak adhesion between the label and the outside surface of the bottle may lead to the label working loose (and in some cases even separating from the bottle completely) during shipping or storing the bottle. Such a weak bond may thus lead to a product that is not attractive to consumers (e.g., a bottle with a loose label) or a product that does not conform to labeling requirements (e.g., Food and Drug Administration (FDA) regulations).
In some instances, transporting and/or storing a labeled bottle may present conditions that expedite adhesive failure. For example, labeled bottles are often subjected to elevated temperatures and/or high humidity during transportation and storage prior to being delivered to retailers. In addition to decreasing the effectiveness of the adhesive, this elevated temperature and/or humidity may cause the bottle and its contents to expand and place increased stresses on the bond, further accelerating adhesive failure. Accordingly, bottling plants, manufacturers, etc., test adhesives used in bottling applications to ensure that the bond will withstand the anticipated conditions during shipping, storage, and the like.
Traditionally, this testing is performed using expensive machinery located at a remote laboratory. At these laboratories, dynamic testing equipment (e.g., an environmental chamber or the like) is used to quantify the strength of an adhesive used during a particular bottling batch. For example, a bottling plant may collect one or more adhesive samples from a particular batch and send them to a laboratory for testing. The laboratory may then subject the one or more samples to a test using equipment which determines how much time is required to cause failure of the adhesive. Generally, the more time required to cause failure indicates a stronger adhesive bond. The results of the test are then returned to the bottling plant or the like, which may then proceed accordingly. For example, if the adhesive performs in an acceptable range, the bottling plant may ship the bottles. Alternatively, if the adhesive does not perform in an acceptable range, the bottling plant may destroy or re-label the bottles (if the bottles have not already shipped).
This testing scheme suffers many drawbacks. For example, the machinery used to test the samples may be expensive and/or require trained personnel to operate in order to obtain accurate results. Accordingly, such equipment may be located offsite causing a significant delay between the time a sample is sent for testing and the time the results are returned. For example, two weeks is a typical turnaround to receive results of an offsite test. In the meantime, the bottling plant may have labeled thousands of bottles which may ultimately be unusable (should the tests indicate the adhesive is ineffective). Further, this traditional testing typically involves only labels and glue (and not the bottle). Thus, these tests cannot predict the effects of “real-world” conditions on the adhesive. For example, these tests are unable to measure the effects of long-term creep on the adhesive caused by an expanding bottle stored at high temperatures.
Accordingly, there remains a need to provide a method and/or apparatus to test the adhesion of a label to an outside surface of a bottle that overcomes one or more of the above deficiencies.